Narrative:

Air carrier X called on climbing to 10000 ft. I turned air carrier X to a 270 degree heading (a 30 degree right turn) and climbed the aircraft to FL230. This was done to avoid cpr Y northeast of fort wayne at 15000 ft. When I realized that the heading might not be enough, I decided to turn air carrier X on course (direct fort wayne) and stop air carrier X at 14000 ft. I thought air carrier X read back 14000 ft and fort wayne, but in actuality, he read back 'direct fort wayne.' when air carrier X was approximately out of 12000 ft, I issued traffic at his 12 O'clock and 10 mi, nebound level at 15000 ft. Air carrier X stated he had the traffic in sight, which in my mind, further enforced the idea of him stopping at 14000 ft. I went on to handle a few more control actions in my sector. I scanned back to air carrier X and noticed at that time the mode C indicated 14100 ft. That still is within tolerances. I asked the aircraft, 'verify you're level at 14000 ft.' his response was, 'negative, we're climbing to FL230.' separation was already lost, so I turned the climbing aircraft 60 degrees right and turned cpr Y to a 090 degree heading. I then advised air carrier X that 'I had stopped his climb at 14000 ft and read him his traffic.' he stated, 'I had the traffic but did not get the new altitude of 14000 ft.' by now, standard separation existed, so I cleared both aircraft on course.

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Original NASA ASRS Text

Title: ACR X CLB THROUGH OCCUPIED ALT HAD LTSS FROM CPR Y. SYS ERROR.

Narrative: ACR X CALLED ON CLBING TO 10000 FT. I TURNED ACR X TO A 270 DEG HDG (A 30 DEG R TURN) AND CLBED THE ACFT TO FL230. THIS WAS DONE TO AVOID CPR Y NE OF FORT WAYNE AT 15000 FT. WHEN I REALIZED THAT THE HDG MIGHT NOT BE ENOUGH, I DECIDED TO TURN ACR X ON COURSE (DIRECT FORT WAYNE) AND STOP ACR X AT 14000 FT. I THOUGHT ACR X READ BACK 14000 FT AND FORT WAYNE, BUT IN ACTUALITY, HE READ BACK 'DIRECT FORT WAYNE.' WHEN ACR X WAS APPROX OUT OF 12000 FT, I ISSUED TFC AT HIS 12 O'CLOCK AND 10 MI, NEBOUND LEVEL AT 15000 FT. ACR X STATED HE HAD THE TFC IN SIGHT, WHICH IN MY MIND, FURTHER ENFORCED THE IDEA OF HIM STOPPING AT 14000 FT. I WENT ON TO HANDLE A FEW MORE CTL ACTIONS IN MY SECTOR. I SCANNED BACK TO ACR X AND NOTICED AT THAT TIME THE MODE C INDICATED 14100 FT. THAT STILL IS WITHIN TOLERANCES. I ASKED THE ACFT, 'VERIFY YOU'RE LEVEL AT 14000 FT.' HIS RESPONSE WAS, 'NEGATIVE, WE'RE CLBING TO FL230.' SEPARATION WAS ALREADY LOST, SO I TURNED THE CLBING ACFT 60 DEGS R AND TURNED CPR Y TO A 090 DEG HDG. I THEN ADVISED ACR X THAT 'I HAD STOPPED HIS CLB AT 14000 FT AND READ HIM HIS TFC.' HE STATED, 'I HAD THE TFC BUT DID NOT GET THE NEW ALT OF 14000 FT.' BY NOW, STANDARD SEPARATION EXISTED, SO I CLRED BOTH ACFT ON COURSE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.